An Asthma Link to Women's Cycle

By DENISE GRADY

Published: September 11, 1996

SOME women with asthma find that they seem more likely to have attacks around the time that their menstrual periods begin. But even though the possibility of such a link was first reported in a medical journal in 1931, it has never been proved or studied extensively.

A study appearing in the current issue of Archives of Internal Medicine provides evidence that the connection is real, and its authors said in interviews that some women who had asthma might benefit from additional treatment with preventive medications to ward off attacks at that time.

The subjects in the study were 182 female patients, ranging in age from 13 to 47, who needed emergency-room treatment for asthma at urban hospitals in Pennsylvania. Researchers found that 46 percent of the patients were in the ''perimenstrual'' phase of their cycles, defined as the sevn-day interval beginning three days before the start of a period. Counting the day that bleeding begins as day 1 of a woman's 28-day cycle, the perimenstrual interval would include days 26 through 4.

Dividing the cycle into three other weeklong intervals -- before, during and after ovulation -- the researchers found that 20 percent of the patients were preovulatory and 24 percent were in the ovulatory phase. Only 10 percent were postovulatory. Because such a large share of the women were in the perimenstrual phase, as compared with those in other phases, the researchers concluded that the hormonal changes that occur as menstruation starts may make some asthmatic women more vulnerable to attacks. Specifically, they blamed the sharp drop in estrogen that normally occurs during the perimenstrual week.

Dr. Emil Skobeloff, the director of the study, said the drops in estrogen levels as menstruation approached might prompt changes in the cells of the immune system and the airways that made asthma attacks more likely. Dr. Skobeloff is an emergency room doctor at Crozer-Chester Medical Center in Upland, Pa., and a clinical assistant professor of emergency medicine at Allegheny University of the Health Sciences in Philadelphia.

About 10 million Americans have asthma. Among adults, about 60 percent of asthmatics are women, but they account for about 75 percent of hospitalizations for the disease. Researchers have not been able to explain why the condition should be more common or more severe among women.

Fluctuations in estrogen may play a role, Dr. Skobeloff suggested, and he recommended that large-scale studies be done to determine whether estrogen therapy to stabilize those levels might help some women with severe asthma that appears related to their cycles.

The causes of asthma are not fully understood. In sensitive people, attacks may be brought on by exposure to dust, smoke, pollens, animal dander, cold air, viruses and many other triggers. Researchers think that an important underlying cause of asthma is inflammation in the airways, brought about when cells of the immune system release irritating substances in response to the triggers. Why some people are prone to such immune responses is not known, but the tendency may be genetic.

Asthma attacks can usually be treated with inhaled drugs known as bronchodilators, available by prescription only, that reopen the airways by relaxing the constricted muscles. But bronchodilators may not work for severe attacks, which can become life-threatening and require emergency-room treatment.

In recent years, researchers have come to believe that the key to controlling asthma lies in treating and preventing chronic inflammation, not just treating the symptoms. Bronchodilators do not help inflammation; steroids and other medications are needed.

Dr. Skobeloff suggested that estrogen, which is a steroid hormone, may help keep inflammation in check for most of a woman's monthly cycle. The best way for a woman with asthma to determine whether she is sensitive to estrogen levels is to chart her symptoms daily for several months and discuss her findings with her doctor, Dr. Skobeloff said. He strongly recommended the use of a peak-flow meter, which is advised for most asthmatics. The device measures the rate at which a person can exhale. Decreases often signal the onset of problems well before symptoms appear.

Doctors usually recommend starting preventive treatment as soon as the peak flow falls below a certain level, which varies for each patient. Dr. Skobeloff said those guidelines should be followed regardless of where a woman was in her cycle.

Asked to comment on Dr. Skobeloff's findings, Dr. Monica Kraft, who treats asthma patients at the National Jewish Center for Immunology and Respiratory Medicine in Denver, said: ''We all know the connection seems to exist for some patients, but it's hard to show it objectively. The utility of this study is its large size.''

Dr. Kraft does not expect the study to change the way she treats patients. ''I would still go with a peak-flow meter rather than a calendar,'' she said.

Dr. Christopher Fanta, an associate professor of medicine at Harvard and clinical director of the Longwood Medical Area Adult Asthma Center at Brigham and Women's Hospital in Boston, said it would make sense for women who noticed asthma flare-ups associated with menstruation to increase preventive medications ahead of time. He emphasized that Dr. Skobeloff's study had shown only an association, but had not proved or explained the link between asthma and the menstrual cycle.